Uber Founder Travis Kalanick Resigns as C.E.O.

The move caps months of questions over the leadership of Uber, which has become a prime example of Silicon Valley start-up culture gone awry. The company has been exposed this year as having a workplace culture that included sexual harassment and discrimination, and it has pushed the envelope in dealing with law enforcement and even partners. That tone was set by Mr. Kalanick, who has aggressively turned the company into the world’s dominant ride-hailing service and upended the transportation industry around the globe.